1. Field of the Disclosure
This disclosure relates in general to a test substrate for non-contact printing. The substrate can be used to optimize process and formulation variables.
2. Description of the Related Art
Non-contact printing processes are being developed for patterning electronic, optical, and biomedical devices—organic light-emitting diode (“OLED”) displays, circuitry, transistor arrays, radio frequency identification (“RFID”) tags, sensors, color filters, drug delivery systems, etc. These typically require precise deposition of a patterned printed layer with a uniform dry thickness. An attractive means for defining the printed pattern uses a reactive surface-active material as this approach has very high resolution and can be applied over many surfaces.
The pattern tolerances, thickness, and uniformity of a printed material depend in a complex and coupled manner on process variables (e.g., print head speed, ink flow rate, temperature, nozzle design), the formulation of the liquid ink (e.g., concentrations of the solvents & solutes, viscosity, surface tension), substrate design (e.g., surface chemistry and roughness, patterns where wetting is desired vs. prohibited), and ink drying. An efficient means is needed for simultaneously optimizing these variables and thus printing quality.